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Adcom GFA-2 Amp Repair


The Monkey

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So it looks like the old B&W speakers are ok, which leaves pretty much only the amp as the culprit. Specifically, it seems like one channel is problematic. The sound it puts out sounds very very muffled, distorted, and scratchy. I opened up the amp and didn't see anything that to my untrained eye appears to be obviously kablooey. However, I did note that one of the fuses on the board looks different than the others. It's not blown but could that be it? Anyone see anything else?

ac177745.png

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The far right fuse looks a little different, but doesn't really mean anything.

Saw one thread on diyaudio regarding these, something about loose RCA grounds:

Seeking help- something caused HUGE noise - diyAudio

Do you have a meter, but just not there? At a minimum I would check the DC offset on both inputs if you have access to a DMM. And I have gotten schematics for free from Adcom just by asking them via email (if it comes to that).

EDIT: A bit of info in this thread as well (see post 34)

http://www.diyaudio.com/forums/solid-state/56735-adcom-gfa535-bad-transformer-3.html

And follow Doug's advice :)

Edited by Pars
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I replaced the fuses on the suspect side. Problem persisted. I then replaced the single fuse that's at the bottom of the picture. Success!

Then the problem returned. :(

Replaced that fuse again. No joy. Problem back where I started. Does this seem like a grounding issue? This is starting to annoy me.

EDIT: also blew out some dust with some compressed air.

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